[Myelination as a modulating factor in memory circuitry]

Abstract

Introduction: Myelin has been understood for many years as a static component that regulates the speed of electrical impulse transmission. However, multiple works defend a dynamic role dependent on experience. This has allowed the development of a new concept called myelin plasticity that contributes, together with synaptic plasticity, to the long-term changes that occur in neuronal circuits during learning and memory. Therefore, this review will address the latest published data regarding the role of myelination with memory.

Development: Evidence from human neuroimaging studies demonstrates that myelination can change due to activity-dependent modulation, such that learning can modify the axon myelination. Alternatively, it has also been shown that interfering with myelination, using transgenic rodent models, significantly impairs memory processes. This has important implications in alterations as severe as Alzheimer's disease, where transcriptional changes and in the phenotype of cells associated with the myelination process begin to be described.

Conclusions: The new knowledge supports the concept of myelin plasticity and its implications for memory, which opens a new opportunity for the treatment of deficits that affect this cognitive function.

Figura 1

Representación esquemática de la mielinización e implicaciones sobre los procesos de memoria. a) Las células precursoras de los oligodendrocitos proliferan y se diferencian en oligodendrocitos premielinizantes; con el tiempo, estos maduran y mielinizan los axones de las neuronas del sistema nervioso central. Nótese cómo un solo oligodendrocito puede mielinizar varios axones; b) Expresión temporal de los genes comentados en esta revisión y efecto de su manipulación genética (caja roja: deleción condicionada; caja verde: sobreexpresión). OL: oligodendrocitos; OPC: células precursoras de los oligodendrocitos. Figura creada parcialmente con BioRender.com.